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Search results for: THERMAL PROPERTIES
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Numerical analysis by FEM and analytical study of the dynamic thermal behavior of hollow bricks with different cavity concentration
PublicationThis paper presents the investigation results on the influence of the cavity concentration in hollow bricks on static and dynamic thermal parameters: a time lag, a decrement factor, an equivalent thermal diffusivity (ETD) and an equivalent thermal conductivity (ETC). The dynamic thermal behavior of hollow bricks is studied with an optimized cavity shape to reduce the intensity of radiation and convective heat exchange. The thermal...
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High level synthesis with adaptive evolutionary algorithm for solving reliability and thermal problems in reconfigurable microelectronic systems.
PublicationPraca dotyczy badań efektywności adaptacyjnego algorytmu ewolucyjnego (AEA)zastosowanego do syntezy wysokiego poziomu układów cyfrowych CMOS w celu zredukowania rozpraszanej przez nie mocy. W wyniku obniżenia poziomu mocy pobieranej przez układ mikroelektroniczny uzyskuje się zmniejszenie szczytowej i średniej temperatury układu scalonego co z kolei prowadzi do wzrostu niezawodności całego systemu. Podczas przeprowadzonych...
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DSC and thermal stability investigation of novel poly(ester-ether) glycolsand poly(ester-ether)urethanes.
PublicationOtrzymano serie nowych poli(estro-etero)dioli z kwasu adypinowgo.........
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Benzene-induced hydro(solvo)thermal synthesis of Cu2+ and Zn2+ coordination polymers based on 1,3-benzenedicarboxylate
PublicationHydro(solvo)thermal reactions of Cu(NO3)2·2.5H2O or Zn(NO3)2·6H2O with 1,3-H2bdc provided two structurally different coordination polymers; a 2D network “metallacalixarene” based on the paddlewheel-type cluster with the formula [Cu(1,3-bdc)·H2O]·H2O (1) and a 3D framework [Zn(1,3-bdc)] (2), respectively. The use of a base was unnecessary in this synthesis; however, the presence of benzene played a crucial role in the crystallization...
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Start-up of a power unit of a thermal power plant auxiliary systems with supply from a hydropower plant
PublicationThis article discusses the issues related to a power unit of a thermal power plant start-up with the use of a hydropower plant. Hydropower plant can supply and will enable start-up of auxiliary equipment in a power unit of a thermal power plant. Due to high capacity of auxiliary drives, start-up of auxiliaries in a thermal power plant after blackout (and boiler shutdown) is not possible from emergency energy sources in the power...
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Analysis of the selection of low temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublicationThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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Analysis of the selection of low-temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublicationThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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Numerical analysis by FEM and analytical study of the dynamic thermal behavior of hollow bricks with different cavity concentration
PublicationThis paper presents the investigation results on the influence of the cavity concentration in hollow bricks on static and dynamic thermal parameters: a time lag, a decrement factor, an equivalent thermal diffusivity (ETD) and an equivalent thermal conductivity (ETC). The dynamic thermal behavior of hollow bricks is studied with an optimized cavity shape to reduce the intensity of radiation and convective heat exchange. The thermal...
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A New Approach of Solidification Analysis in Modular Latent Thermal Energy Storage Unit Based on Image Processing
PublicationThe solidification process of RT18HC in a cylindrical shell and tube storage unit has been studied using a new methodology based on image processing. The main idea of the algorithm is to label the region of solidification and use statistical functions to calculate the dimensions of the solidification front over time. Said analysis includes two methods. The first method is to measure the solid fraction changes during solidification....
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Electro-thermal buckling of elastically supported double-layered piezoelectric nanoplates affected by an external electric voltage
PublicationPurpose Thermal buckling of double-layered piezoelectric nanoplates has been analyzed by applying an external electric voltage on the nanoplates. The paper aims to discuss this issue. Design/methodology/approach Double-layered nanoplates are connected to each other by considering linear van der Waals forces. Nanoplates are placed on a polymer matrix. A comprehensive thermal stress function is used for investigating thermal buckling....
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Real-Time Monnitoring of Vegetable Oils' Thermal Degradation Using Proton Transfer Reaction Mass Spectrometry
PublicationThe volatile aldehydes, which are generated during frying, can be harmful to human health, therefore the concentration of these compounds in frying fumes should be monitored. In addition, aldehydes are markers of oils’ quality, and so it is possible to determine shelf-life or suitability for frying of these oils. Commonly, in order to determine aldehydes concentration gas chromatography is performed, however it does not allow for...
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Thermal and economic investigation of straight and U-bend double tube heat exchanger with coiled wire turbulator
PublicationExperimental research has been carried out for four individual heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend and U-bend with turbulator. Tests were made for the water-water system. The study covered a wide measuring range, i.e., Re = 800–9000 – on the shell side, for a constant cold water temperature of 9 ◦C and hot water of 50 ◦C. The heat exchangers were made from copper tubes with...
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Rheology of Variable Viscosity‐Based Mixed Convective Inclined Magnetized Cross Nanofluid with Varying Thermal Conductivity
PublicationCross nanofluid possesses an extraordinary quality among the various fluidic models to explore the key characteristics of flowing fluid during very low and very high shear rates and its viscosity models depend upon shear rate. The current study establishes the numerical treatment regarding variable viscosity‐based mixed convective inclined magnetized Cross nanofluid with var‐ ying thermal conductivities over the moving permeable...
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Experimental and numerical investigation on shell and coil storage unit with biodegradable PCM for modular thermal battery applications
PublicationThermal energy storage (TES) in automotive applications is currently growing in importance. TES can visibly reduce primary energy consumptions, decrease CO2 emission, and improve thermal comfort in electric as well as hybrid vehicles. However, to meet the new ambitious target (15% reduction of CO2 emissions in the new cars until 2025) it is required to use plug-in electric vehicles. For this reason, this paper focuses on the optimization...
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Significant Production of Thermal Energy in Partially Ionized Hyperbolic Tangent Material Based on Ternary Hybrid Nanomaterials
PublicationNanoparticles are frequently used to enhance the thermal performance of numerous materials. This study has many practical applications for activities that have to minimize losses of energy due to several impacts. This study investigates the inclusion of ternary hybrid nanoparticles in a partially ionized hyperbolic tangent liquid passed over a stretched melting surface. The fluid motion equation is presented by considering the...
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Defining the thermal conductivity of thermally heterogeneous hollow wall bricks used as elements for increasing the comfort of buildings
PublicationThe article presents numerical calculation analysis in the scope of determining thermal conductivity coefficientλeq[W/(m·K)] of thermally heterogeneous hollow bricks of thermally heterogeneous structure (a combinationof structural material with thermal insulation material). Numerical calculations were conducted by means ofprofessional software TRISCO-KOBRU 86, serving thermal circulation analysis in a 2D field in stationary approach.The...
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Thermal efficiency investigations on the self-ignition test engine fed with marine low sulfur diesel fuels
PublicationWithin the article an issues of implementing the new kinds of marine diesel fuels into ships’ operation was described taking into ac-count restrictions on the permissible sulphur content introduced by the International Maritime Organization. This is a new situation for ship owners and fuel producers, which forces the necessity to carry out laboratory research tests on especially adapted engine stands. How to elaborate the method...
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Structural properties of hypothetical CeBa2Cu3O7 compound from LSDA+DMFT calculations
PublicationThe hypothetical stoichiometric CeBa2Cu3O7 (Ce123) compound, which has not been synthesized as a single phase yet, was studied by the density functional theory (DFT). We utilized a method which merges the local spin density approximation (LSDA) with the dynamical mean-field theory (DMFT) to account for the electronic correlations. The LSDA+DMFT calculations were performed in the high-temperature range. The particular emphasis was...
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Flow structure, heat transfer and scaling analysis in the case of thermo-magnetic convection in a differentially heated cylindrical enclosure
PublicationThe experimental, numerical and scaling analysis in the case of thermo-magnetic convection in a thermosyphon-like enclosure filled with a paramagnetic fluid is presented. Visualization of temperature field together with the numerical simulation gave an information about the flow structure, which indicated “finger-like” structures of hot and cold streams advecting each other. Their number depended on the Rayleigh number and also...
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Novel Approaches of Using of Spirulina Platensis in Natural Rubber Based Composites
PublicationThe aim of this work was to investigate the influence of Spirulina (Spirulina platensis) as a natural filler on the curing characterization, morphology and mechanical, thermomechanical and thermal properties of natural rubber (NR) based composites. Spirulina was introduced into NR mixture in amount of 0 phr, 10 phr and 30 phr. The vulcanization process was carried out at the determined process condition by using hydraulic press...
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Bis-phosphonated carbon nanotubes: one pot synthesis and their application as efficient adsorbent of mercury
PublicationEffective, one-pot method of CNTs phosphonylation is presented. Cheap and readily available reagents are used, so the process can be easily transferred to large-scale production. The product was analyzed using spectroscopic methods (FTIR, UV-vis, XPS). Thermal properties of the bis-phosphonated nanotubes are reported for the first time. Newly obtained material was tested as an adsorbent for mercury removal from water. The sorption...
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MXene-based materials for removal of antibiotics and heavy metals from wastewater– a review
PublicationAs a novel family of 2D materials, MXenes provide an extensive variety of applications in water and effluent treatment due to their distinctive properties and attractive applicability, including superior electrical conductivity, higher thermal stability, hydrophilicity, and high sorption-reduction capacity. Their excellent sorption selectivity makes them perfect for removing hazardous contaminants. Currently, MXene-based materials...
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Experiments on compression ignition engine powered by nano-fuels
PublicationThe use of nanoparticles in fuels provides new opportunities for modification of fuel properties, which may affect the operational parameters of engines, in particular the efficiency and fuel consumption. The paper presents comparison of compression ignition engine performance fuelled with neat diesel and nano-diesel. Alumina (Al2O3) was used as nanoparticles. Surface-active substances, including Span 80 surfactant, as well as...
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Investigating the Impact of Curing System on Structure-Property Relationship of Natural Rubber Modified with Brewery By-Product and Ground Tire Rubber
PublicationThe application of wastes as a filler/reinforcement phase in polymers is a new strategy to modify the performance properties and reduce the price of biocomposites. The use of these fillers, coming from agricultural waste (cellulose/lignocellulose-based fillers) and waste rubbers, constitutes a method for the management of post-consumer waste. In this paper, highly-filled biocomposites based on natural rubber (NR) and ground tire...
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Nanostructuring of thin Au films deposited on ordered Ti templates for applications in SERS
PublicationIn this work the results on thermal nanostructuring of the Au films on Ti templates as well as morphology and optical properties of the obtained structures are reported. The bimetal nanostructures are fabricated in a multi-step process. First, the titania nanotubes are produced on the surface of Ti foil by anodization in an ethylene glycol-water solution containing fluoride ions. This is followed by chemical etching in oxalic acid...
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Modeling of wood frame structures with different insulation materials under damaging dynamic loading
PublicationWood frame buildings are very popular in regions that are exposed to different dynamic excitations, such as damaging earthquakes. Their seismic resistance is really important in order to prevent structural damages and human losses. This paper presents the results of advanced numerical investigation carried out using the FEM. Based on the models of wall panels, the numerical model of real structure of the wood frame building has...
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Diamine derivatives of dimerized fatty acids and bio-based polyether polyol as sustainable platforms for the synthesis of non-isocyanate polyurethanes
PublicationA series of environmentally friendly non-isocyanate polyurethanes (NIPUs) were successfully prepared via the polyaddition reaction of bio-based polyether polyol-based cyclic carbonate with diamine derivative of dimerized fatty acids. The syntheses of NIPUs were realized by the three-step method in the absence of toxic solvents and, importantly, the process of carbonation did not require the use of elevated pressure. The effect...
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CO2 Separation Using Supported Deep Eutectic Liquid Membranes Based on 1,2-propanediol
PublicationIn this work, deep eutectic solvents (DESs) composed of choline chloride, acetylcholine chloride or tetrabutylammonium chloride, and 1,2-propanediol were used as a liquid phase for polypropylene-based supported liquid membranes (SLMs) and evaluated for the separation of carbon dioxide from CO2/N2 mixtures. Fourier transform infrared spectra were obtained to confirm DES formation, and the thermal stability of solvents was investigated...
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Impact and stretching standardized tests as useful tools for assessment of viscoelastic behavior for highly rubberized asphalt binder
PublicationAsphalt binder is generally identified as a brittle material at low service temperature or under high-speed load, and the brittleness becomes serious after weathering aging. Improving the toughness of asphalt binder through adding high-content of crumb tire rubber is an efficient method to solve this problem. Devulcanized rubber modified asphalt binder (DRMA) with different contents (15–40%) of devulcanized rubber (DR) were prepared...
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Novel Research on Biomedical Polyurethanes
PublicationThe variety of mechanical properties characterizes properly designed PURs. They may be biocompatible and reveal compatibility with blood, making them attractive materials for the fabrication of tissue scaffolds; however, like all synthetic materials, PURs don’t reveal sufficient biocompatibility. PURs may undergo certain chemical modifications (e.g., 1,4:3,6-dianhydro-D-sorbitol, ascorbic acid (AA), growth factors, covering with...
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The Thermal State of the North Atlantic Ocean and Hydrological Droughts in the Warta River Catchment in Poland during 1951–2020
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Thermal, spectroscopic and luminescence investigations of lanthanide(III) coordination polymers based on V-shaped 4,4′-sulfonyldibenzoic acid
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Implementation of a Non-Thermal Atmospheric Pressure Plasma for Eradication of Plant Pathogens from a Surface of Economically Important Seeds
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Thermal degradation behavior of lignin-modified porous styrene-divinylbenzene and styrene-bisphenol A glycerolate diacrylate copolymer microspheres
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Effect of thermal modification of oak wood on sawdust granularity = Utecaj termicke modifikacije na granulometrijski sastav piljevine
PublicationW pracy przedstawiono wyniki badania składu granolumetrycznego trocin po przecinaniu na pilarce ramowej wielopiłowej PRW15M drewna dębowego (przed i po obróbce termicznej). Wykazano, że uzyskiwane trociny z drewna po modyfikacji termicznej charakteryzują się większym udziałem frakcji drobnych.
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/sup 6/LiI(Eu) in neutron and /spl gamma/-ray spectrometry-a highly sensitive thermal neutron detector
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Thermal performance of building envelopes with structural layers of the same density: Lightweight aggregate concrete versus foamed concrete
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Numerical Simulation and Experimental Analysis of Thermal Cycles and Phase Transformation Behavior of Laser-Welded Advanced Multiphase Steel
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Synthesis of reduced graphene oxide nanosheets using nanofibers from methane and biogas thermal decomposition with various catalysts
PublicationReduced graphene oxide and graphene oxide (rGO, GO) were synthesised from carbon nanofibers, which were formed in catalytic thermal decomposition of methane (CDM) and biogas with different catalysts used in the process. The aim of the work was valorization of CDM carbon nanofiber products. The samples were characterized using Raman spectra, a scanning electron microscope and a transmission electron microscope. As a result, we observe...
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Comprehensive stabilization of all streams of solid residues formed during sewage sludge thermal treatment – Case study
PublicationModern wastewater treatment plants are currently struggling with the problem of processing and ecological management of sewage sludge. Thermal utilization is a frequently used practice of excess sludge utilization especially in large wastewater treatment plants, which seems to be a quite promising concept. However, during thermal treatment, fractions of ashes and dusts are generated. Such wastes, especially the dust fraction, can...
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Fully bio-based poly(propylene succinate) synthesis and investigation of thermal degradation kinetics with released gases analysis
PublicationOne of the most important information about polyesters is their thermal stability and phase transition tem- peratures. These characteristics give information about the promising behavior of the polyester during proces- sing. In this work, linear bio-based polyester polyols were prepared with the use of succinic acid and 1.3- propanediol (both with natural origin). As a polycondensation catalyst was used tetraisopropyl orthotitanate...
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Comparison of the exponential thermal transient parameterization methods with the SMTP method in the unipedicled DIEP flap computer modelling and simulation
PublicationThe aim of this paper is to compare the spatial contrast of the image descriptors obtained via three different thermal transient parameterization methods in Active Dynamic Thermography. The thermal constants and amplitude values of the one- and two- exponential parametrization are compared to the Simplified Magnitude-Temporal Parametrization method (SMTP). The comparison is performed using the data obtained by simulating the cold...
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The motion influence on respiration rate estimation from low-resolution thermal sequences during attention focusing tasks
PublicationGlobal aging has led to a growing expectancy for creating home-based platforms for indoor monitoring of elderly people. A motivation is to provide a non-intrusive technique, which does not require special activities of a patient but allows for remote monitoring of elderly people while assisting them with their daily activities. The goal of our study was to evaluate motion performed by a person focused on a specific task and check...
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Mathematical modeling and prediction of pit to crack transition under cyclic thermal load using artificial neural network
PublicationThe formation of pitting is a major problem in most metals, which is caused by extremely localized corrosion that creates small holes in metal and subsequently, it changes into cracks under mechanical load, thermo-mechanical stress, and corrosion process factors. This research aims to study pit to crack transition phenomenon of steel boiler heat tubes under cyclic thermal load, and mathematical modeling...
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Thermal Tomography in Medicine. 9th European Congress of Thermology, Kraków, 29.05-01.06.2003. Tomografia termiczna w medycynie.
PublicationArtykuł prezentuje możliwości zastosowań techniki tomografii termicznej w aplikacjach medycznych. Dyskutowane są możliwości i ograniczenia prezentowanej metody w odniesieniu do organizmów żywych.
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Nowy system diagnostyki cieplno-przepływowej obiektów energetycznych.The new system of power units thermal and flow diagnostics.
PublicationPrzedstawiono zmodernizowany system diagnostyki urządzeń składowych obiegów cieplnych bloków energetycznych. Wskazano na zalety zastosowania do tego sztucznych sieci neuronowych (SSN). Opisano dokładność SSN zastosowanych do poszukiwania typów degradacji geometrycznych i do rozpoznawania rozmiarów degradacji geometrycznych.
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Experimental investigation of thermal energy storage in shell-and-multi-tube unit with nano-enhanced phase change material
PublicationThis paper deals with thermal energy storage with use of nanoparticle enhanced phase change material in shell-and-multitube unit. The experiments are conducted under atmospheric pressure. Paraffin wax and two different fatty acids are used as base phase change material. Graphite and multi-walled carbon nanotubes serve as nanoparticles. Graphite nanoparticles are tested at the concentrations of 0.1%, 1% and 5% by weight, while multi-walled...
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Utilization of glass fibres as supports for surface compounds for generation of gaseous standard mixtures using thermal decomposition technique
PublicationPrzy oznaczaniu analitów na śladowym lub ultraśladowym poziomie stężeń, szczególnie w przypadku próbek o złożonym lub niejednorodnym składzie matrycy, analityk napotyka dodatkowe trudności techniczne i metodyczne związane z walidacją stosowanych procedur. Niezbędne jest zatem dysponowanie odpowiednimi wzorcami (lub lepiej materiałami odniesienia), które swoim składem są jak najbardziej zbliżone do składu próbek rzeczywistych. W...
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Preparation of gaseous standard mixtures: methods for controlling the amount of components generated in the process of thermal decomposition of immobilized compounds.
PublicationGazowe mieszaniny wzorcowe odgrywają ważną rolę w ocenie metod analitycznych i urządzeń pomiarowych. W tym przypadku gazowe mieszaniny wzorcowe mogą być traktowane jako specjalny rodzaj materiału odniesienia.Proces walidacji wymaga użycia tzw. matrycowych materiałów odniesienia. Wybór techniki umożliwiającej uzyskanie gazowej mieszaniny wzorcowej o żądanych parametrach użytkowych zależy od natury składników mierzonych i gazu...
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Analysis of the possibility of increasing thermal-electric energy conversion ratio in CHP units based on micro gas turbine
PublicationThe aim of this paper is to analyze the possibility of increasing thermal energy to electricity conversion efficiency in combined heat and power (CHP) units based on micro gas turbine during low heat demand periods. At the beginning sustainable development postulates under power engineering are explained. Next micro CHP as part of distributed generation idea is presented. The main part of the article is based on results of thermodynamic...